1. Field of the Invention
The present invention relates to an optical information recording apparatus, a method for recording optical information, an optical information recording medium, an optical information processing apparatus, and a method for accessing an optical information recording medium, and is applicable to, for example, an optical disk and an optical disk apparatus. The present invention detects a laser beam irradiation position for recording additional information modulated in accordance with a result of the position detection at a prescribed position, and thereby makes it possible to easily determine whether an optical disk is an illegal copy or not.
2. Description of the Related Art
Conventionally, an optical disk such as a compact disk and a Digital Versatile Disk (DVD) has been designed so that its information recording surface is divided into a plurality of concentric circles and an International Federation of the Phonographic Industry (IFPI) code is recorded at the innermost concentric circle with the object of preventing illegal copies.
That is, the compact disk, the DVD and the like are designed so that a recording area for Table Of Contents (TOC) is formed on the outer circumferential side to the innermost concentric circle where the IFPI code has been recorded and user data such as audio data recorded in outer circumferential areas following to the TOC data recording area can be accessed on the TOC data.
On the other hand, the IFPI code is made up of caved seals composed of symbols indicating a maker, a factory, a disk number and the like, formaking it possible to determine whether the optical disk is an illegal copy or not byverifying the source and so on of the optical disk by means of checking with a human eye.
Now, if an optical disk apparatus, which reproduces such a kind of optical disk, can determine on its side whether a loaded optical disk is an illegal copy or not and execute a treatment in accordance with a result of the determination, it is considerable that the interest of a copyright holder can effectively be protected.
In this case, a method is conceivable where it is determined whether an optical disk is an illegal copy or not by utilizing the IFPI code. However, there is a problem that it is difficult to easily determine whether an optical disk is an illegal copy or not on the optical disk apparatus side by utilizing the IFPI code because the IFPI code is made for the verification using a human eye. In addition, there is another problem that an illegal copy with a copied IFPI code itself is difficult to be determined under this method.
The present invention was made from consideration of the aforementioned matters, and aims to propose an optical information recording apparatus, a method for recording optical information, an optical information recording medium for being applied to those apparatus and method, an optical information processing apparatus for accessing the optical information recording medium, and a method for accessing the optical information recording medium, which are capable of easily determining whether an optical disk is an illegal copy or not.
For resolving such problems, according to the first embodiment of the present invention, there is provided an optical information recording apparatus detecting a first irradiation position by a first laser beam with reference to a reproduction signal, generating a modulating signal by modulating additional information in accordance with the position detection result and modulating a second laser beam by the modulating signal to irradiate an optical information recording medium with the modulated second laser beam, and then irradiating a second irradiation position distant from the first irradiation position by the first laser beam by a prescribed distance at least in a direction perpendicular to a track with the modulated second laser beam.
According to the first embodiment, by selecting the prescribed distance suitably, the additional information such as a disk identification code can be recorded in a manner that it is difficult to copy the additional information without substantially damaging the reproduction of the ordinal information recorded as a pit train or a mark train. Besides, by processing a reproduction signal detected at the time of reproducing the ordinal information recorded as the pit train or the mark train, the additional information recorded in a manner described above can be reproduced. Consequently, it becomes possible to determine whether an optical disk is an illegal copy or not on the additional information.
Furthermore, according to the second embodiment of the present invention, there is provided a method for recording an optical information detecting a first irradiation position by a first laser beam with reference to a reproduction signal, generating a modulating signal by modulating additional information in accordance with the position detection result and modulating a second laser beam by the modulating signal to irradiate an optical information recording medium with the modulated second laser beam, and then irradiating a second irradiation position distant from the first irradiation position by the first laser beam by a prescribed distance at least in a direction perpendicular to a track with the modulated second laser beam.
According to the second embodiment, advantages similar to those of the first embodiment can be obtained.
Furthermore, according to the third embodiment of the present invention, there is provided an optical information recording medium including additional information to a data recorded on a track composed of a first pit train or a first mark train, which information is recorded as a second pit train or a second mark train disposed substantially parallel to the track at a position distant from the track by a prescribed distance, and which prescribed distance is set to be a distance where a signal level of are production signal, which varies in accordance with the first pit train or the first mark train, varies in accordance with the additional information when the reproduction signal is detected by irradiating the track with a laser beam on the track.
According to the third embodiment, advantages similar to those of the first embodiment can be obtained.
Furthermore, according to the fourth embodiment of the present invention, there is provided an optical information processing apparatus for detecting a reproduction signal, a signal level of which varies in accordance with a first pit train or a first mark train, by irradiating a track composed of the first pit train or the first mark train with a laser beam, and reproducing additional information formed by a second pit train or a second mark train formed in the vicinity of the track on a cross talk component mixed to the reproduction signal by processing the reproduction signal.
According to the fourth embodiment, the additional information recorded as the second pit train or a second mark train formed in the vicinity of the track can also be reproduced by utilizing an optical system for reproducing the information recorded on the track. Consequently, the additional information recorded in a manner that it is difficult to be copied can be reproduced with a simple structure. Hence, it becomes possible to determine whether an optical disk is an illegal copy or not with reference to the reproduced additional information.
Furthermore, according to the fifth embodiment of the present invention, there is provided an optical information processing apparatus detecting a reproduction signal, a signal level of which varies in accordance with a first pit train or a first mark train, by irradiating a track composed of the first pit train or the first mark train with a laser beam, and reproducing additional information formed by a second pit train or a second mark train formed in the vicinity of the track on a cross talk component mixed to the reproduction signal.
According to the fifth embodiment, advantages similar to those of the fourth embodiment can be obtained.